Subaru EX13 Service Manual page 104

Problem and possible cause
1 . Oil leakage
2 . Oil up
1 . Fuel system
2 . Engine core components
1 . Ignition system problems
2 . Fuel system problems
3 . Cylinder head
4 . Valve system problems
1) Loose oil drain plug
2) Faulty oil drain gasket
3) Loose main bearing cover bolts
4) Faulty main bearing cover gasket
5) Crankshaft oil seal (front, rear) defect
1) Faulty piston oil ring
2) Piston ring seizure, wear or poor contact
3) Excessive wear of piston and/or cylinder
4) Faulty stem seal
5) Excessive oil level
6) Breather defect
1) Clogged air cleaner
2) Faulty throttle body
1) Low compression
2) Overcooling
1) Loose ignition system wiring
2) Improper or faulty spark plug
1) Lean or rich fuel/air mixture
2) Throttle body contamination
3) Dirty or clogged fuel lines
4) Air mixing from air intake system joints
1) Carbon deposit in combustion chamber
2) Leakage from cylinder head gasket
1) Improper valve clearance
2) Valve heat deterioration
3) Worn or broken valve spring
4)Improper valve timing
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Remedy
Tighten
Replace
Tighten
Replace
Replace
Replace
Replace
Replace
Replace
Adjust oil level
Repair or replace
Clean or replace
Repair or replace
Check and repair
Check and adjust load and/or
engine speed
Inspect and tighten
Clean or replace
Clean, adjust or replace throttle
body
Inspect, adjust, or replace
Clean or replace
Tighten; replace gasket
Clean
Replace
Adjust
Replace
Replace
Adjust